Been kicking around a few thoughts, and started thinking what possible threat could be even remotely powerful enough to "unleash" the trinity of Alicia/Megaira/Tisiphone upon.

The more I thought about it, the more I keep coming back to the Rish. They've already manipulated the original Federation vs Empire into going to war with each other, and then flipped several agents such as Colonel Watts, not to mention inspiring much of the command of an entire Sector to try splitting off from the Empire. If the Rish have already done all of that, it only stands to reason they'll try again, and again and again, trying to destabilize the Empire so they can expand some more.

Since Alicia's new psychic talents are likely classified well above top-secret and probably in the realm of read before self-termination, by both Uncle Arthur and O Branch, nobody knows what she's capable of. We might also see her calling in a marker from Clan Theryian. I'm sure they'd be only to happy to burn another Clan in retaliation for the Sphere trying to kill ALL of Clan Theryian years before (Revenge is a dish best served cold, seems a popular Rish mantra)

Some form of story against the FALA is possible, although unlikely, FALA isn't really a large enough threat to throw Alicia at them. She'd roll up entire cells in no time, and about the only story would be Alicia's angst at carrying weapons for FALA terrorist cells, and how early/late she can report it to the authorities without killing any innocents she swore to protect as a Wasp.

I'd broadly agree. My thoughts are as follows for any future exploration of the universe:

1 - FALA, as noted, is not a credible opponent. Mind you, they are essentially someone's minions in the existing story and only a genuine threat to the cadre when handed out-of-context quantities of intel and wargear.

2 - The Rish are a good default enemy.

2a - The Rish, based on what we've seen of them, seem frankly better at cross-species intel work than humanity. Therefore it's not an unreasonable assumption that no matter what super-duper-platinum level-triple-omega-burn-before-reading classification Keita and O Branch slap on the Furies, they will eventually find out some broadly accurate version of it (depending on how much of the details they believe), especially if the narrative jumps, say, five or ten years again.

2b - The Rish's main disadvantage is in HMI (okay, technically RMI - Rishthan-Machine-Interface!) cybernetics, which leaves them at a 3-1 power disadvantage in fleet actions and means even a clan mother's personal guard are basically target practice to a cadre spearpoint. Alicia Devries represents a step change in capability over even the cyber-syth or alpha-synth - a psy-synth - further hammering the Rish's disadvantage

2c - She's apparently also developed telepathic abilities as a result, which is new for humans (and credible because the Quarl already have them), and that capability threatens to undermine the Rish's big advantage - their apparent skill at suborning humans

2d - Just because it's the result of what's reported as some wierd accident doesn't mean the humans won't figure it out or be able to duplicate the process

2e - Devries was able to interface with an Alpha-synth despite manifestly not having the implant capability to do so. Looked at from a Rish perspective, whatever happened to her might (if Rish-ified) represent a (superior!) alternative to the cyber-synth link they can't use themselves, putting them on a par with humanity for fleet actions

2f - The Rish are an enemy empire that's the only true peer to Murphy's domain. Ultimately, if they know about Alicia and decide they need to capture or kill her, they can do so. It'd cost them an unholy butchers bill, but if they decide to do so they can throw enough gunships and battlesuited infantry at the furies to literally run her out of ammunition....

3 - The other option - if something happened once it can happen again. We don't (even Tisiphone doesn't) know what happened to the gods, but the point is they were real. Which means any number of slightly supernatural influences could also be real. We don't know where they went, or why, or what could bring them back. If the furies were real, why not Cacodemons, who are broadly similar beings with a not entirely dissimilar MO but much more malevolent ends.